Tuesday, March 15, 2011

Proccessor packages

- The old standard for chip design.
- Will always have an even numbers of pins.
- Pin count can be as low as 4 and as high as 68
- In μps, this is used in older 8086, 8088 and 8026 models.

PIN GRID ARRAY

- The rows are changed to an array of pins.
- A square chip with several rows of pins evenly spaced around the perimeter of the chip to form the array.

- Two PGA sockets

a) regular - Chip is inserted the same way as DIP
b) ZIF - Zero Insertion Force, has a lever machanism that will open the socket and allow the chip to be inserted w/ no force.

- In μps, this is used in 80286, 80386, 80486, Pentium, Celeron and most non-Intel processors.

- Different modifications of PGA

º Stagered Pin-Grid Array (SPGA) - Used in Pentium processors, which staggers the arrangement of the pins to allow them to fit closer together.

º The Pentium Pro, because it has seperate chips for theCPU and the Level 2cache, uses a design called the multichip module (MCM). An MCM is a package that contains more than one chip.

º Tape-Carrier Package (TCP) - Which is as thin as phographic film and is soldered to the motherboard.

º Single-Edge Contact (sec) cartridge, used for the Pentium ll. This is actually a PGA package mounted on a small daughtercard tat attaches to the motherboard through a single-edge connector The SEC is a highly appealing in design, because it takes up less space on the motherboard and has better electrical characteristics.

Organic land Grid Array (ool or OLGA).

- The OLGA chips uses a flip chip design, where the processor is attached to the substrate facedown for better signal integrity, more efficient heat removal and lower inductance Used by the Pentium 4 processor, which has 423 pins.